[PATCH] D65253: [sanitizer_common] Replace forkpty with posix_spawn on Darwin

[Julian Lettner via Phabricator via llvm-commits]

yln created this revision.
Herald added subscribers: llvm-commits, Sanitizers, kubamracek.
Herald added projects: Sanitizers, LLVM.

On Darwin, we currently use forkpty to communicate with the "atos"
symbolizer. There are several problems that fork[pty] has, e.g. that
after fork, interceptors are still active and this sometimes causes
crashes or hangs. This is especially problematic for TSan, which uses
interceptors for OS-provided locks and mutexes, and even Libc functions
use those.

This patch replaces forkpty with posix_spawn on Darwin. Since
posix_spawn doesn't fork (at least on Darwin), the interceptors are not
a problem. Another benefit is that we'll handle post-fork failures (e.g.
sandbox disallows "exec") gracefully now.

Related revisions and previous attempts that were blocked by or had to
be revered due to test failures:
https://reviews.llvm.org/D48451
https://reviews.llvm.org/D40032


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D65253

Files:
  compiler-rt/lib/sanitizer_common/sanitizer_mac.cc
  compiler-rt/lib/sanitizer_common/sanitizer_posix.h
  compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_internal.h
  compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_libcdep.cc
  compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_mac.cc
  compiler-rt/lib/sanitizer_common/sanitizer_symbolizer_posix_libcdep.cc

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